Grab mm lock before grabbing pt lock
Subsystems (3)
Sasha Levin
maintainerPATCH 1/2 Grab mm lock before grabbing pt lock
From: Maksym Planeta <[email protected]>
[ Upstream commit 6d002348789bc16e9203e9818b7a3688787e3b29 ]
Function xen_pin_page calls xen_pte_lock, which in turn grab page table lock (ptlock). When locking, xen_pte_lock expect mm->page_table_lock to be held before grabbing ptlock, but this does not happen when pinning is caused by xen_mm_pin_all.
This commit addresses lockdep warning below, which shows up when suspending a Xen VM.
[ 3680.658422] Freezing user space processes
[ 3680.660156] Freezing user space processes completed (elapsed 0.001 seconds)
[ 3680.660182] OOM killer disabled.
[ 3680.660192] Freezing remaining freezable tasks
[ 3680.661485] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[ 3680.685254]
[ 3680.685265] ==================================
[ 3680.685269] WARNING: Nested lock was not taken
[ 3680.685274] 6.12.0+ #16 Tainted: G W
[ 3680.685279] ----------------------------------
[ 3680.685283] migration/0/19 is trying to lock:
[ 3680.685288] ffff88800bac33c0 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: xen_pin_page+0x175/0x1d0
[ 3680.685303]
[ 3680.685303] but this task is not holding:
[ 3680.685308] init_mm.page_table_lock
[ 3680.685311]
[ 3680.685311] stack backtrace:
[ 3680.685316] CPU: 0 UID: 0 PID: 19 Comm: migration/0 Tainted: G W 6.12.0+ #16
[ 3680.685324] Tainted: [W]=WARN
[ 3680.685328] Stopper: multi_cpu_stop+0x0/0x120 <- __stop_cpus.constprop.0+0x8c/0xd0
[ 3680.685339] Call Trace:
[ 3680.685344] <TASK>
[ 3680.685347] dump_stack_lvl+0x77/0xb0
[ 3680.685356] __lock_acquire+0x917/0x2310
[ 3680.685364] lock_acquire+0xce/0x2c0
[ 3680.685369] ? xen_pin_page+0x175/0x1d0
[ 3680.685373] _raw_spin_lock_nest_lock+0x2f/0x70
[ 3680.685381] ? xen_pin_page+0x175/0x1d0
[ 3680.685386] xen_pin_page+0x175/0x1d0
[ 3680.685390] ? __pfx_xen_pin_page+0x10/0x10
[ 3680.685394] __xen_pgd_walk+0x233/0x2c0
[ 3680.685401] ? stop_one_cpu+0x91/0x100
[ 3680.685405] __xen_pgd_pin+0x5d/0x250
[ 3680.685410] xen_mm_pin_all+0x70/0xa0
[ 3680.685415] xen_pv_pre_suspend+0xf/0x280
[ 3680.685420] xen_suspend+0x57/0x1a0
[ 3680.685428] multi_cpu_stop+0x6b/0x120
[ 3680.685432] ? update_cpumasks_hier+0x7c/0xa60
[ 3680.685439] ? __pfx_multi_cpu_stop+0x10/0x10
[ 3680.685443] cpu_stopper_thread+0x8c/0x140
[ 3680.685448] ? smpboot_thread_fn+0x20/0x1f0
[ 3680.685454] ? __pfx_smpboot_thread_fn+0x10/0x10
[ 3680.685458] smpboot_thread_fn+0xed/0x1f0
[ 3680.685462] kthread+0xde/0x110
[ 3680.685467] ? __pfx_kthread+0x10/0x10
[ 3680.685471] ret_from_fork+0x2f/0x50
[ 3680.685478] ? __pfx_kthread+0x10/0x10
[ 3680.685482] ret_from_fork_asm+0x1a/0x30
[ 3680.685489] </TASK>
[ 3680.685491]
[ 3680.685491] other info that might help us debug this:
[ 3680.685497] 1 lock held by migration/0/19:
[ 3680.685500] #0: ffffffff8284df38 (pgd_lock){+.+.}-{3:3}, at: xen_mm_pin_all+0x14/0xa0
[ 3680.685512]
[ 3680.685512] stack backtrace:
[ 3680.685518] CPU: 0 UID: 0 PID: 19 Comm: migration/0 Tainted: G W 6.12.0+ #16
[ 3680.685528] Tainted: [W]=WARN
[ 3680.685531] Stopper: multi_cpu_stop+0x0/0x120 <- __stop_cpus.constprop.0+0x8c/0xd0
[ 3680.685538] Call Trace:
[ 3680.685541] <TASK>
[ 3680.685544] dump_stack_lvl+0x77/0xb0
[ 3680.685549] __lock_acquire+0x93c/0x2310
[ 3680.685554] lock_acquire+0xce/0x2c0
[ 3680.685558] ? xen_pin_page+0x175/0x1d0
[ 3680.685562] _raw_spin_lock_nest_lock+0x2f/0x70
[ 3680.685568] ? xen_pin_page+0x175/0x1d0
[ 3680.685572] xen_pin_page+0x175/0x1d0
[ 3680.685578] ? __pfx_xen_pin_page+0x10/0x10
[ 3680.685582] __xen_pgd_walk+0x233/0x2c0
[ 3680.685588] ? stop_one_cpu+0x91/0x100
[ 3680.685592] __xen_pgd_pin+0x5d/0x250
[ 3680.685596] xen_mm_pin_all+0x70/0xa0
[ 3680.685600] xen_pv_pre_suspend+0xf/0x280
[ 3680.685607] xen_suspend+0x57/0x1a0
[ 3680.685611] multi_cpu_stop+0x6b/0x120
[ 3680.685615] ? update_cpumasks_hier+0x7c/0xa60
[ 3680.685620] ? __pfx_multi_cpu_stop+0x10/0x10
[ 3680.685625] cpu_stopper_thread+0x8c/0x140
[ 3680.685629] ? smpboot_thread_fn+0x20/0x1f0
[ 3680.685634] ? __pfx_smpboot_thread_fn+0x10/0x10
[ 3680.685638] smpboot_thread_fn+0xed/0x1f0
[ 3680.685642] kthread+0xde/0x110
[ 3680.685645] ? __pfx_kthread+0x10/0x10
[ 3680.685649] ret_from_fork+0x2f/0x50
[ 3680.685654] ? __pfx_kthread+0x10/0x10
[ 3680.685657] ret_from_fork_asm+0x1a/0x30
[ 3680.685662] </TASK>
[ 3680.685267] xen:grant_table: Grant tables using version 1 layout
[ 3680.685921] OOM killer enabled.
[ 3680.685934] Restarting tasks ... done.Message-ID: <[email protected]>
--- arch/x86/xen/mmu_pv.c | 4 ++++ 1 file changed, 4 insertions(+)
arch/x86/xen/mmu_pv.c +4 -0
@@ -766,6 +766,7 @@ void xen_mm_pin_all(void) {struct page *page; +spin_lock (&init_mm.page_table_lock);spin_lock (&pgd_lock);list_for_each_entry (page, &pgd_list, lru) {
@@ -776,6 +777,7 @@ void xen_mm_pin_all(void) }spin_unlock (&pgd_lock); +spin_unlock (&init_mm.page_table_lock); } static void __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
@@ -872,6 +874,7 @@ void xen_mm_unpin_all(void) {struct page *page; +spin_lock (&init_mm.page_table_lock);spin_lock (&pgd_lock);list_for_each_entry (page, &pgd_list, lru) {
@@ -883,6 +886,7 @@ void xen_mm_unpin_all(void) }spin_unlock (&pgd_lock); +spin_unlock (&init_mm.page_table_lock); }static void xen_activate_mm (struct mm_struct *prev,struct mm_struct *next)
Signature · 1 line
2.39.5
Sasha Levin
maintainerPATCH 2/2 selftests: gpio: gpio-sim: Fix missing chip disablements
From: Koichiro Den <[email protected]>
[ Upstream commit f8524ac33cd452aef5384504b3264db6039a455e ]
Since upstream commit 8bd76b3d3f3a ("gpio: sim: lock up configfs that an instantiated device depends on"), rmdir for an active virtual devices been prohibited.
Update gpio-sim selftest to align with the change.
--- tools/testing/selftests/gpio/gpio-sim.sh | 31 +++++++++++++++++++----- 1 file changed, 25 insertions(+), 6 deletions(-)
tools/testing/selftests/gpio/gpio-sim.sh +25 -6
@@ -46,12 +46,6 @@ remove_chip() { rmdir $CONFIGFS_DIR/$CHIP || fail "Unable to remove the chip" } -configfs_cleanup() { - for CHIP in `ls $CONFIGFS_DIR/`; do - remove_chip $CHIP - done -} - create_chip() { local CHIP=$1
@@ -105,6 +99,13 @@ disable_chip() { echo 0 > $CONFIGFS_DIR/$CHIP/live || fail "Unable to disable the chip" } +configfs_cleanup() { + for CHIP in `ls $CONFIGFS_DIR/`; do + disable_chip $CHIP + remove_chip $CHIP + done +} + configfs_chip_name() { local CHIP=$1 local BANK=$2
@@ -181,6 +182,7 @@ create_chip chip create_bank chip bank enable_chip chip test -n `cat $CONFIGFS_DIR/chip/bank/chip_name` || fail "chip_name doesn't work" +disable_chip chip remove_chip chip echo "1.2. chip_name returns 'none' if the chip is still pending"
@@ -195,6 +197,7 @@ create_chip chip create_bank chip bank enable_chip chip test -n `cat $CONFIGFS_DIR/chip/dev_name` || fail "dev_name doesn't work" +disable_chip chip remove_chip chip echo "2. Creating and configuring simulated chips"
@@ -204,6 +207,7 @@ create_chip chip create_bank chip bank enable_chip chip test "`get_chip_num_lines chip bank`" = "1" || fail "default number of lines is not 1" +disable_chip chip remove_chip chip echo "2.2. Number of lines can be specified"
@@ -212,6 +216,7 @@ create_bank chip bank set_num_lines chip bank 16 enable_chip chip test "`get_chip_num_lines chip bank`" = "16" || fail "number of lines is not 16" +disable_chip chip remove_chip chip echo "2.3. Label can be set"
@@ -220,6 +225,7 @@ create_bank chip bank set_label chip bank foobar enable_chip chip test "`get_chip_label chip bank`" = "foobar" || fail "label is incorrect" +disable_chip chip remove_chip chip echo "2.4. Label can be left empty"
@@ -227,6 +233,7 @@ create_chip chip create_bank chip bank enable_chip chip test -z "`cat $CONFIGFS_DIR/chip/bank/label`" || fail "label is not empty" +disable_chip chip remove_chip chip echo "2.5. Line names can be configured"
@@ -238,6 +245,7 @@ set_line_name chip bank 2 bar enable_chip chip test "`get_line_name chip bank 0`" = "foo" || fail "line name is incorrect" test "`get_line_name chip bank 2`" = "bar" || fail "line name is incorrect" +disable_chip chip remove_chip chip echo "2.6. Line config can remain unused if offset is greater than number of lines"
@@ -248,6 +256,7 @@ set_line_name chip bank 5 foobar enable_chip chip test "`get_line_name chip bank 0`" = "" || fail "line name is incorrect" test "`get_line_name chip bank 1`" = "" || fail "line name is incorrect" +disable_chip chip remove_chip chip echo "2.7. Line configfs directory names are sanitized"
@@ -267,6 +276,7 @@ for CHIP in $CHIPS; do enable_chip $CHIP done for CHIP in $CHIPS; do + disable_chip $CHIP remove_chip $CHIP done
@@ -278,6 +288,7 @@ echo foobar > $CONFIGFS_DIR/chip/bank/label 2> /dev/null && \ fail "Setting label of a live chip should fail" echo 8 > $CONFIGFS_DIR/chip/bank/num_lines 2> /dev/null && \ fail "Setting number of lines of a live chip should fail" +disable_chip chip remove_chip chip echo "2.10. Can't create line items when chip is live"
@@ -285,6 +296,7 @@ create_chip chip create_bank chip bank enable_chip chip mkdir $CONFIGFS_DIR/chip/bank/line0 2> /dev/null && fail "Creating line item should fail" +disable_chip chip remove_chip chip echo "2.11. Probe errors are propagated to user-space"
@@ -316,6 +328,7 @@ mkdir -p $CONFIGFS_DIR/chip/bank/line4/hog enable_chip chip $BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 4 2> /dev/null && \ fail "Setting the value of a hogged line shouldn't succeed" +disable_chip chip remove_chip chip echo "3. Controlling simulated chips"
@@ -331,6 +344,7 @@ test "$?" = "1" || fail "pull set incorrectly" sysfs_set_pull chip bank 0 pull-down $BASE_DIR/gpio-mockup-cdev /dev/`configfs_chip_name chip bank` 1 test "$?" = "0" || fail "pull set incorrectly" +disable_chip chip remove_chip chip echo "3.2. Pull can be read from sysfs"
@@ -344,6 +358,7 @@ SYSFS_PATH=/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull test `cat $SYSFS_PATH` = "pull-down" || fail "reading the pull failed" sysfs_set_pull chip bank 0 pull-up test `cat $SYSFS_PATH` = "pull-up" || fail "reading the pull failed" +disable_chip chip remove_chip chip echo "3.3. Incorrect input in sysfs is rejected"
@@ -355,6 +370,7 @@ DEVNAME=`configfs_dev_name chip` CHIPNAME=`configfs_chip_name chip bank` SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/pull" echo foobar > $SYSFS_PATH 2> /dev/null && fail "invalid input not detected" +disable_chip chip remove_chip chip echo "3.4. Can't write to value"
@@ -365,6 +381,7 @@ DEVNAME=`configfs_dev_name chip` CHIPNAME=`configfs_chip_name chip bank` SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value" echo 1 > $SYSFS_PATH 2> /dev/null && fail "writing to 'value' succeeded unexpectedly" +disable_chip chip remove_chip chip echo "4. Simulated GPIO chips are functional"
@@ -382,6 +399,7 @@ $BASE_DIR/gpio-mockup-cdev -s 1 /dev/`configfs_chip_name chip bank` 0 & sleep 0.1 # FIXME Any better way? test `cat $SYSFS_PATH` = "1" || fail "incorrect value read from sysfs" kill $! +disable_chip chip remove_chip chip echo "4.2. Bias settings work correctly"
@@ -394,6 +412,7 @@ CHIPNAME=`configfs_chip_name chip bank` SYSFS_PATH="/sys/devices/platform/$DEVNAME/$CHIPNAME/sim_gpio0/value" $BASE_DIR/gpio-mockup-cdev -b pull-up /dev/`configfs_chip_name chip bank` 0 test `cat $SYSFS_PATH` = "1" || fail "bias setting does not work" +disable_chip chip remove_chip chip echo "GPIO $MODULE test PASS"
Signature · 1 line
2.39.5